AR vs E28, which is correct??

[scar]

One of the reasons I started using the term E28 was after seeing it used in the description in several parts catalogs like Macs and Snyders.
The other reason is because I used to call it an AR and every time I did, someone would say that, "there is no such thing as an AR. AR came from a worker's notes and was never an official term used by Ford." I'm hoping that someone has some concrete proof as to the correct term.